在 tkinter 中显示传感器读数答案

【问题标题】：Display Sensor Reading in tkinter在 tkinter 中显示传感器读数
【发布时间】：2020-08-06 09:37:46
【问题描述】：

我已将流量传感器与树莓派接口。我希望每秒在 tkinter gui 上更新此读数。请帮助我编写代码。

import RPi.GPIO as GPIO
import time
GPIO.setmode(GPIO.BOARD)
flowin =7
GPIO.setup(7,GPIO.IN)
rate=0
seconds=0
pulse=550
time_new = 0.0
#numlist=list()

while True:
    y=2
    time_new = time.time() + 1
    rate_cnt = 0
    #y=numlist.append(x)
    while time.time() <= time_new:
        x=GPIO.input(flowin)
        if y!=x:
            if GPIO.input(flowin)!= 0:
                rate+= 1
            y=x
    seconds+=1
    litre=rate/pulse
    minutes=seconds/60
    flowrate=litre/minutes
    #print("flowrate",flowrate)

【问题讨论】：

标签： python tkinter raspberry-pi sensors

【解决方案1】：

您可以使用 thread 读取传感器读数并更新与 tkinter Label 关联的 StringVar 以显示 flowrate。

以下是基于您的代码的示例：

import RPi.GPIO as GPIO
import tkinter as tk
import time
import threading

def read_sensor():
    GPIO.setmode(GPIO.BOARD)
    flowin =7
    GPIO.setup(7,GPIO.IN)
    rate=0
    seconds=0
    pulse=550
    time_new = 0.0
    #numlist=list()

    while True:
        y=2
        time_new = time.time() + 1
        rate_cnt = 0
        #y=numlist.append(x)
        while time.time() <= time_new:
            x=GPIO.input(flowin)
            if y!=x:
                if GPIO.input(flowin)!= 0:
                    rate+= 1
                y=x
        seconds+=1
        litre=rate/pulse
        minutes=seconds/60
        flowrate=litre/minutes
        #print("flowrate",flowrate)
        # update the tkinter label via StringVar
        var.set(f'flowrate: {flowrate:10.2f}')

# create the thread
task = threading.Thread(target=read_sensor, daemon=True)

root = tk.Tk()

var = tk.StringVar()
lbl = tk.Label(root, textvariable=var, width=40, height=5, font=('Consolas', 24, 'bold'))
lbl.pack()

task.start() # start the reading thread
root.mainloop()

【讨论】：